Hermetic compressor with insulated discharge tube

ABSTRACT

A refrigerant compressor incorporating insulated discharge tube means for preventing undesirable heat transfer between the relatively hot refrigerant in the discharge tube and the relatively cool refrigerant in the compressor between the compression mechanism and the outer housing thereof. The insulated discharge tube means will also prevent undesirable heat transfer between the relatively hot refrigerant in the discharge tube and the lubricant in the lubricant sump within the outer housing. In a modification, the insulated discharge tube means may be comprised of tubes disposed one within the other, with one or both of the tubes being corrugated so as to enhance flexibility of the insulated discharge tube means and thereby reduce or obviate transmission of vibration from the compression mechanism to the outer housing of the compressor.

United States Patent 1 Parker et al.

[ HERMETIC COMPRESSOR WITH INSULATED DISCHARGE TUBE [75] Inventors: Sidney A. Parker, Fort Worth, Tex.;

Seymour Rothstein, Highland Park, Ill.

[73] Assignee: Lennox Industries Inc.,

Marshalltown, Iowa [22] Filed: Jan. 27, 1975 [21] Appl. No.: 544,190

[52] US. Cl. 62/296; 62/295; 62/115; 62/498; 62/508 [51] Int. Cl.'- F25D 19/00 [58] Field of Search 62/295, 296, 508, 498,

[56] References Cited UNITED STATES PATENTS 2,039,053 4/1936 Bixler 62/295 2,101,881 12/1937 Terry 62/295 2,857,746 10/1958 Philipp 62/295 3,302,424 2/l967 Scherzinger 62/296 51 Dec. 16, 1975 Primary Examiner-William J. Wye Attorney, Agent, or Firm-Molinare, Allegretti, Newitt & Witcoff [57] ABSTRACT A refrigerant compressor incorporating insulated discharge tube means for preventing undesirable heat transfer between the relatively hot refrigerant in the discharge tube and the relatively cool refrigerant in the compressor between the compression mechanism and the outer housing thereof. The insulated discharge tube means will also prevent undesirable heat transfer between the relatively hot refrigerant in the discharge tube and the lubricant in the lubricant sump within the outer housing. In a modification, the insulated discharge tube means may be comprised of tubes disposed one within the other, with one or both of the tubes being corrugated so as to enhance flexibility of the insulated discharge tube means and thereby reduce or obviate transmission of vibration from the compression mechanism to the outer housing of the compressor.

16 Claims, 4 Drawing Figures U.S. Patent Dec. 16, 1975 HERMETIC COMPRESSOR WITH INSULATED DISCHARGE TUBE BACKGROUND AND SUMMARY OF THE INVENTION resiliently mounted within an outer housing. A dis charge tube communicates hot refrigerant gas compressed within the compression mechanism to the refrigeration system exterior of .the outer housing of the compressor. In one type of compressor construction, the relatively cool suction gas returning from the refrigeration system is introduced into the refrigerant compressor in the space between the compression mechanism and the outer housing. In such arrangement the discharge tube passes through said space and therefore the relatively hot discharge gas is in heat transfer relationship with the relatively cool suction gas. This could result in undesirable superheating of the suction gas.

In addition, in some refrigerant compressors, a lubricant sump is provided in the bottom of the outer housing and the discharge tube passes through the lubricant in the sump for sound deadening purposes. In such arrangement, the relatively hot discharge gas in the discharge tube is in heat transfer relationship with the lubricant in the sump and may undesirably heat the lubricant so as to reduce the viscosity of same and thereby undesirably reduce the lubricating properties of the lubricant. This could cause improper lubrication of the bearing surfaces and possible problems in compressor operation and life.

An object of the present invention is to provide an improved refrigerant compressor incorporating an insulated discharge tube for improving operating efflciencies of the compressor.

Another object of this invention is to provide a refrigerant compressor with a discharge tube that is insulated so as to prevent undesirable heat transfer between the relatively hot refrigerant in the discharge tube and the relatively cool refrigerant in the space between the compression mechanism and outer housing of the refrigerant compressor in a compressor having a suction gas cooled motor.

Another object of the present invention is to provide an improved refrigerant compressor wherein the discharge tube is insulated so as to prevent undesirable heat transfer between the relatively hot refrigerant in the discharge tube and the lubricant in the lubricant sump in the outer housing of the refrigerant compressor.

Still another object of the present invention is to provide an improved refrigerant compressor comprised of tube means disposed one within the other, with the tube means being flexible to reduce transmission of vibration from the compression mechanism to the outer housing of the refrigerant compressor.

Other objects and advantages of the present invention will be made more apparent hereinafter.

BRIEF DESCRIPTION OF THE DRAWING There is illustrated in the attached drawing a presently preferred embodirrient of the present invention wherein:

FIG. 1 shows an elevation view of a refrigerant compressor embodying the novel insulated discharge tube of this invention, with parts being broken away and other parts being in section to better illustrate the invention;

FIG. 2 is an enlarged elevation view, with parts broken away, to better show the construction of the insulated discharge tube;

FIG. 3 is a partial elevation view of a modified insulated discharge tube, with parts broken away for clarity; and

FIG. 4 is a partial elevation view of a further modification of an insulated discharge tube, with parts broken away for clarity.

DETAILED DESCRIPTION OF THE PRESENT INVENTION Referring now to FIG. 1 there is illustrated a refriger- 1 ant compressor 10 embodying the principles of the present invention. The refrigerant compressor I0 includes an outer housing comprising an upper shell 12 hermetically sealed to a lower shell 14. Legs 16 are secured to the lower shell 14 as for example by welding in order to provide means for supporting the refrigerant compressor in use.

Mounted within the refrigerant compressor is a compression mechanism 18. The compressor mechanism 18 may be resiliently supported within the outer housing by spring means 20 secured between the inner surface of the outer housing and the compression mechamsm.

The compression mechanism includes a housing 22 having cylinder means 24 defined therein. The end of the cylinder means 24 is closed by a head assembly 26 retained by suitable retaining means 27.-A piston 28 is operable within the cylinder means 24 and cooperates with a discharge and suction valve assembly 29 in order to receive relatively cool refrigerant and compress same. The piston 28 is actuated by a drive shaft 30 which is operatively connected to the rotor 32 of the electric motor 34. The stator 36 of the motor 34 is inductively connected to the rotor 32 to drive same.

In operation, a refrigerant compressor 10 is connected in a refrigeration system such that relatively cool vaporous refrigerant returns from a suction line 38 and enters the space 40 between the outer housing and the compression mechanism 18. The suction gas will pass over motor 34 to cool same and will enter the cylinder means 24 through the passageway 42 in the housing 22. On the suction stroke of piston 28, suction gas will be drawn into the cylinder means 24 through the suction valve in the discharge and suction valve assembly 29 and on the discharge stroke the gas will be compressed and forced through the discharge and suction valve assembly 29 into the discharge tube 44 connected to the head 27, from which it will be carried to the discharge line exterior of the compressor 10.

A feature of this invention is the provision of an imperforate tubular member 46 on the discharge tube 44 in order to insulateihe relatively hot discharge gas therein from the lubriun-. in the lubricant sump and from the relativel can I suction gas in space 40. As shown in FIGJ the "tubular member 46 extends about 3 that portion of the discharge tube 44 that is in heat transfer relationship with the lubricant sump 41 formed in the lower portion of the lower shell 14 of the outer housing. A second imperforate tubular member 48 is disposed about the discharge tube 44 in the space 40 between the compression mechanism and the outer housing in the same manner as tube 46 in order to insulate the relatively hot vaporous refrigerant within the discharge tube 44 from the relatively cool vaporous refrigerant in the space between the compression mechanism and the outer housing.

It is readily appreciated that the tube members 46 and 48 may be formed from an integral member or unitary member so as to insulate the discharge tube 44 from both the lubricant in the sump and the suction gas in the space between the compression mechanism and the outer housing. If desired, in a particular application, tube 48 may be reduced in length to cover a smaller part of the discharge tube 44 or may be omitted.

.Tuming to FIG. 2 there is illustrated on an enlarged scale the discharge tube 44 and the imperforate tubular member 46 thereon. It is seen that there is a vacuum chamber 50 defined between the discharge tube 44 and the imperforate tubular member 46. There is a short tube 52 secured to the imperforate tubular member 46 for assisting in drawing the vacuum in the vacuum chamber 50. The insulated discharged tube may be manufactured by securing vacuum drawing equipment to the end of the tube 52 and drawing the desired vacuum on the order of 500 microns or less in the vacuum chamber 50. Then the end of tube 52 is welded shut as indicated at 54. The insulated discharge tube is then ready to be secured in place within a refrigerant compressor.

One advantage of the present invention is that undesirable heat transfer between the relatively hot dis charge gas within the discharge tube and the oil in the lubricant sump 'is materially minimized so as to overcome lubrication problemsthat might result from undesired heating of theoil. Another advantage to the present invention is that heat transfer between the relatively hot discharge gas in the discharge tube and the suction gas in the space between the compression mechanism and the outer housing is reduced so as to obviate undesirable superheating of the suction gas.

It has been found that the discharge gas loses about 30F. from the space between the discharge and suction valve assembly and the cylinder head and the point of departure of refrigerant from the'refrigerant compressor at predetermined rating conditions of 45F evaporator temperature; l25F condenser temperature; 65F. return gas temperature; and zero subcooling. In such design which utilizes 100 percent of the suction gas for motor cooling, the suction gas gains about 20 before entering the motor. When this gain in suction gas temperature is prevented or substantially reduced, capacity increases are realized-due to the increased density of the suction gas at the cylinders and the efficiency increases resulting from cooler motor temperatures. Preliminary testing indicates that reduc ing internal suction gas temperatures within a refrigerant compressor that is percent suction gas motor cooled by F. resulted in a gain of about 3 percent in capacity and efficiency. The efficiency gain can be restated as follows. A refrigerant compressor with a 9.0 BTU per watt hour input will increase to 9.26 BTU per 4 watt hours if the suction gas is 20F. cooler when it arrives at the motor windings to effectuate cooling.

With reference to FIGS. 3 and 4, there are shown modified insulated discharge tubes which provide for greater flexibility of the insulated discharge tube and minimize or obviate transmission of vibration from the compression mechanism to the shell or outer casing of the compressor.

In FIG. 3, there is shown an outer tube 146 having an inner tube 144 therein. The tubes 144, 146 are each corrugated so as to provide lengthwise flexibility. The inner tube 144 may be surrounded with reinforcement material 145, e.g., braided wire. The inner tube 144 may be connected to the compression mechanism through coupler tube 1440 that is suitably connected at one end to the cylinder head 26 (FIG. 1) and at the other end to tube 144.

If desired, the corrugations may extend over the length of tubes 144, 146 within the outer housing of the compressor or alternatively, the corrugations or bellows may be provided in only portions of the length of tubes 144, 146 within the outer housing, e.g. the bend or turn portions, or a straight portion as shown.

It will be understood that the outer tube 146 will be joined to the inner tube 144 so as to form a vacuum chamber 150 that performs in the same fashion as chamber 50 in the device of FIGS. 1 and 2.

g In FIG. 4, there is shown a modification wherein the inner tube 44 is the same configuration as in FIGS. 1 and 2 and the outer tube 146 is corrugated, as in the modification of FIG. 3. A vacuum chamber 150 is defined between the tubes 44, I46. In some applications, corrugating or forming hollows of the length of tube 146 or part thereof will provide sufficient flexibility to obviate or substantially minimize vibration transmission from the compression mechanism to the outer housing of the compressor, as might result where the discharge tube means is connected rigidly at its ends to the compression mechanism and outer housing.

While I have shown several embodiments of the present invention, it will be apparent to others skilled in the art that other forms may be effected within the scope of the following claims.

What we claim is: a

I. In a refrigerant compressor having compression mechanism for compressing a refrigerant and a discharge tube communicating with the compression mechanism for forwarding the relatively hot refrigerant to a refrigeration system, said compression mechanism being within an outer housing, a lubricant sump within the outer housing, said discharge tube being in heat exchange relationship with the lubricant in the lubricant sump, the improvement wherein an imperforate tubular member is disposed about the discharge tube in heat transfer relation with the lubricant sump in such manner as to insulate the discharge tube from the lubricant.

2. A refrigerant compressor as in claim 1 wherein the tubular member defines a vacuum chamber about the discharge tube between said member and said tube.

3. A refrigerant compressor as in claim 2 wherein relatively cool vaporous refrigerant is in the outer housing and the tubular member and vacuum chamber insulate the relatively hot refrigerant in the discharge tube from the relatively cool vaporous refrigerant in the outer housing.

4. In a refrigerant compressor having compression mechanism for compressing a refrigerant, a discharge tube communicating with the compression mechanism for forwarding hot vaporous refrigerant to a refrigeration system, said compression mechanism being within an outer housing, a suction line for returning relatively cool refrigerant to the refrigerant compressor from the refrigeration system, said discharge tube being in heat exchange relationship with the relatively cool refrigerant returned to the outer housing from the suction line, the improvement wherein an imperforate tubular member is disposed about the discharge tube in heat exchange relation with the relatively cool refrigerant in the outer housing in such manner as to insulate the hot and cool refrigerant from one another.

5. A refrigerant compressor as in claim 4 wherein the tubular member defines a vacuum chamber about the discharge tube.

6. A refrigerant compressor as in claim 4 including a lubricant sump in the outer housing, said tubular member and vacuum chamber insulating the lubricant in the lubricant sump from the relatively hot vaporous refrigerant in the discharge tube.

7. A refrigerant compressor as in claim 6 wherein the vacuum in the vacuum chamber is on the order of 500 microns.

8. A refrigerant compressor as in claim 4 wherein the compression mechanism is driven by an electric-drive motor that is cooled by the relatively cool refrigerant within the outer housing of the refrigerant compressor, said relatively cool refrigerant being returned from the suction line to the space between the outer housing and the compression mechanism.

9. A refrigerant compressor as in claim 1 wherein the discharge tube is corrugated at least in part so as to provide flexibility of same and thereby reduce transmission of vibration from the compression mechanism.

10. A refrigerant compressor as in claim 1 wherein the tubular member is corrugated at least in part so as 6 to provide for flexibility of same and thereby reduce transmission of vibration from the compression mechanism.

11. A refrigerant compressor as in claim 1 wherein the discharge tube and the tubular member have corrugated portions so as to provide for flexibility and thereby reduce transmission of vibration from the compression mechanism to the outer housing.

12. In a refrigerant compressor having compression mechanism within an outer housing, discharge tube means communicating with the compression mechanism and extending from the outer housing for communicating relatively hot refrigerant to a refrigerant system, a suction line for returning relatively cool refrigerant to the compressor from the refrigerant system, said discharge tube means being in heat exchange relationship with the cool refrigerant returned to the compressor from the suction line, the improvement wherein said discharge tube means comprises an inner discharge tube and an outer imperforate tubular member defining a chamber about the discharge tube, said discharge tube means having bellows portions to minimize transmission of vibration from the compression mechanism to the outer housing.

13. A refrigerant compressor as in claim 12 wherein the discharge tube is provided with at least one bellows portion.

14. A refrigerant compressor as in claim 12 wherein the tubular member is provided with at least one bellows portion.

15. A refrigerant compressor as in claim 12 wherein both the discharge tube and the tubular member are provided with corrugations forming bellows portions.

16. A refrigerant compressor as in claim 15 wherein reinforcement means is provided to strengthen the bellows portions in use and prevent rupture thereof. 

1. In a refrigerant compressor having compression mechanism for compressing a refrigerant and a discharge tube communicating with the compression mechanism for forwarding the relatively hot refrigerant to a refrigeration system, said compression mechanism being within an outer housing, a lubricant sump within the outer housing, said discharge tube being in heat exchange relationship with the lubricant in the lubricant sump, the improvement wherein an imperforate tubular member is disposed about the discharge tube in heat transfer relation with the lubricant sump in such manner as to insulate the discharge tube from the lubricant.
 2. A refrigerant compressor as in claim 1 wherein the tubular member defines a vacuum chamber about the discharge tube between said member and said tube.
 3. A refrigerant compressor as in claim 2 wherein relatively cool vaporous refrigerant is in the outer housing and the tubular member and vacuum chamber insulate the relatively hot refrigerant in the discharge tube from the relatively cool vaporous refrigerant in the outer housing.
 4. In a refrigerant compressor having compression mechanism for compressing a refrigerant, a discharge tube communicating with the compression mechanism for forwarding hot vaporous refrigerant to a refrigeration system, said compression mechanism being within an outer housing, a suction line for returning relatively cool refrigerant to the refrigerant compressor from the refrigeration system, said discharge tube being in heat exchange relationship with the relatively cool refrigerant returned to the outer housing from the suction line, the improvement wherein an imperforate tubular member is disposed about the discharge tube in heat exchange relation with the relatively cool refrigerant in the outer housing in such manner as to insulate the hot and cool refrigerant from one another.
 5. A refrigerant compressor as in claim 4 wherein the tubular member defines a vacuum chamber about the discharge tube.
 6. A refrigerant compressor as in claim 4 including a lubricant sump in the outer housing, said tubular member and vacuum chamber insulating the lubricant in the lubricant sump from the relatively hot vaporous refrigerant in the discharge tube.
 7. A refrigerant compressor as in claim 6 wherein the vacuum in the vacuum chamber is on the order of 500 microns.
 8. A refriGerant compressor as in claim 4 wherein the compression mechanism is driven by an electric-drive motor that is cooled by the relatively cool refrigerant within the outer housing of the refrigerant compressor, said relatively cool refrigerant being returned from the suction line to the space between the outer housing and the compression mechanism.
 9. A refrigerant compressor as in claim 1 wherein the discharge tube is corrugated at least in part so as to provide flexibility of same and thereby reduce transmission of vibration from the compression mechanism.
 10. A refrigerant compressor as in claim 1 wherein the tubular member is corrugated at least in part so as to provide for flexibility of same and thereby reduce transmission of vibration from the compression mechanism.
 11. A refrigerant compressor as in claim 1 wherein the discharge tube and the tubular member have corrugated portions so as to provide for flexibility and thereby reduce transmission of vibration from the compression mechanism to the outer housing.
 12. In a refrigerant compressor having compression mechanism within an outer housing, discharge tube means communicating with the compression mechanism and extending from the outer housing for communicating relatively hot refrigerant to a refrigerant system, a suction line for returning relatively cool refrigerant to the compressor from the refrigerant system, said discharge tube means being in heat exchange relationship with the cool refrigerant returned to the compressor from the suction line, the improvement wherein said discharge tube means comprises an inner discharge tube and an outer imperforate tubular member defining a chamber about the discharge tube, said discharge tube means having bellows portions to minimize transmission of vibration from the compression mechanism to the outer housing.
 13. A refrigerant compressor as in claim 12 wherein the discharge tube is provided with at least one bellows portion.
 14. A refrigerant compressor as in claim 12 wherein the tubular member is provided with at least one bellows portion.
 15. A refrigerant compressor as in claim 12 wherein both the discharge tube and the tubular member are provided with corrugations forming bellows portions.
 16. A refrigerant compressor as in claim 15 wherein reinforcement means is provided to strengthen the bellows portions in use and prevent rupture thereof. 